Control means



June 7, 1938.

L. W. EGGLESTON Er AL CONTROL MEANS Filed Sept. 28, 1933 2 Sheets-Sheet l Ficsl Fie.4

m 2. a 5 M-WQQM' g INVENTORS ,8 1% J. 1m W M4 /JM% ATTORNEY June 7, 1938. L. w. EGGLESTON El AL 2,120,213

CONTROL MEANS Filed Sept. 28, 1933 2 Sheets-Sheet 2 Patented June 7, 1938 I CONTROL MEANS Lewis Eggleston and Earnest J. Dillman, Detroit, Mich. assignors to Detroit Lubricator Company, Michigan Detroit, Mich.,

a corporation of Application September 28, 1933, Serial No. 691,350

17- Claims.

Our invention relates to new and useful improvements in control means, and more particularly to a device for use in connection with and for controlling the operation of a mechanical refrigerating system.

An object of our invention is to provide a device by which the average temperature of the space or of the refrigerant evaporator may be regulated or controlled.

Another object is to provide means for causing defrosting of the refrigerant evaporator.

Another object is to provide a defrosting control means operable in conjunction with the normal control means for the system to permit automatically reestablishment of the normal refrigerating cycle-after the system has been defrosted.

Another object is to provide a safety means for stopping operation of the system in the event that the compressor is overloaded.

Another object is to provide means by which the system may be manually started and stopped.

The invention consists in the improvedconstru'ction and combination of parts, to'be more fully described hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specification, we have fully and clearly illustrated a preferred embodiment of our invention, in which drawings Figure 1 is a view of our novel control device in front elevation, and having the front cover or closure member removed to show the internal construction;

Fig. 2 is. a vertical, central section on the line 2-2- of Fig.4;

Fig. 3 is a detail view in vertical section on the line 3-3 of Fig. 1;

Fig. 4 is a view in vertical section on the line 2-4 of Fig. 1, showing the front closure or cover member in place;

Fig. 5 is a detail top plan view of certain manual adjusting means, and

Fig. 6 is a detail bottom plan view in section on the line 6-6 of Fig. 2.

Referring to the drawings by characters of reference, l designates, generally, a main casing or housing having a bottom wall 2, end walls 3, 4, and a rear wall 5. The top of the casing is closed by a substantially rectangular plate Gsecured to' the casing by screws I, or the like.

toward the end wall 4, as shown in Figs. 1 and 2. Extending from the partition 8 there is a substantially horizontal partition l0 connecting the same to the end wall 4 and forming .with a front vertical partition II and with the partition 3 and the casing side walls a compartment or chamber I 2. The forwardly extending partition 3 is joined to the end wall 3 by a substantially horizontal partition l3 adjacent the top of the casing.

Extending downward from the underside of the bottom wall 2 at the end of the casing adjacent the end wall 3, there is a substantially rectangular, hollow element It having a substantially cylindrical, internal bore 15 therethrough and opening upward into the interior of the casing I.

The lower or bottom open end of the bore II is closed by a supporting plate or member ll, preferably secured to the element It by screws, or the like, l1. Mounted on the supporting memher It there is a power element or means, designated generally l8, preferably comprising a substantially cylindrical, circumferentially corrugated, expansible-collapsible, resilient element l9, such as a metal bellows, which is secured and hermetically sealed by solder, or the like, at one end, as at 20, to the supporting member It. The other or upper end of the bellows I9 is closed and sealed by a head member 2| having an externally screw-threaded shank or stem 22 to receive an internally threaded, flanged sleeve 23 providing a guide member and with the flange 24 thereof serving as a stop. The sleeve 23 extends through a guide aperture 25 in a guide and stop plate member 26 fixed to the supporting member It, the flange 24 cooperating with the member 23 to limit upward movement of the head 2| and expansion of the chamber 21 contained within the power element. Through the supporting member [6 there is a central aperture 21' which receives one end of a conduit member 21', having its other end terminating at and in communication with one end of a substantially cylindrical bulb element 21. The other end of the element 2.! is provided with a filling tube 2'! by which the bulb element 21, and the chamber 21 may be charged with a suitable volatile liquid such as .methyl chloride, after which the tube 21* would be hermetically sealed, for example by solder. Screw-threaded as at 23, or otherwise secured. in or to the head 2|, there is an upward projecting thrust pin 29 having a substantially conical, pointed end portion. The thrust pin 23 seats in a substantially conical recess or socket 30 provided in a bearing member 3i which is rigidly secured to a lever member 32. The lever member 36. is provided with depending side flanges 33, 3E. The lever member 32 is fulcrumed or pivotally supported on a shaft or pivot pin 35 which extends transversely through the flanges 33, 34 and which is supported at its opposite ends in bearing bosses 38, 31 projecting from the end wall 3, which are adjacent and'preferably integral with the bottom wall 2. In the top face of the bearing member 3| there is a substantially conical recess or socket 38 which receives the substantially conical, pointed end portion of a thrust member 39 carried by and depending from a spring follower member 40. Seating on the member 48 there is one end of a helical coil spring 4| provided at its other end with a recessed end plate 42 seating against an adjustable abutment member 43, preferably in the form of a screw, threaded and adjustably supported in an internally threaded sleeve 44 secured in and opening through the horizontal partition l3. The spring 4| acts through the lever member 32 to resist operation of the lever member by the power element l8 and determines the force required to be exerted by the power element to actuate the lever member, the spring 4i serving as a range determining means. The lever flanges 33, 34 terminate substantially midway between the casing end walls 3, 4 and are provided at their terminal end portionswith top and bottom stop faces 45, 46 respectively which cooperate respectively with the inclined underface 8 and with 'the top face of the bottom wall 2 to limit the upward and downward throw of the lever member 32. Intermediate the side flanges 33, 34 there is a downward stepped portion 41 which lies beneath the partition 8 and which is spaced laterally from the flanges 33, 34. The end faces of the side flanges 33, 34 which are directed toward the end wall 4 are provided with bearing notches 48, preferably substantially v-shaped, to receive the knife edges 49 of a lever member 58 fulcrumed thereby on the lever member 32. The lever member 58 is provided with an end recess 5! into which the stepped portion 41 extends, and it is also provided with spaced guide fingers 52 which lie between and cooperate with the lever flanges 33, M. to prevent lateral displacement of the lever members relative to each other and to maintain the knife edges laterally in engagement with their respective bearing notches. Clamped to the top and bottom faces of the lever member 50 there are electric insulating plates 53, 54, preferably rigidly secured thereto by rivets, or the like, 55. Projecting from the side edges of the lever member 58 there are opposite spring supporting arms 56. A pair of toggle springs 57, preferably of the helical coil type is provided, each having one end secured to one of the arms 56, preferably by hooking the spring end through eyelets provided in the arms. The other ends of the springs 5! are secured to laterally extending, oppositely directed arms 58 projecting from the bottom edges of the lever flanges 33, 34 adjacent the bearing member 3i. Positioned between the plates 53, 54 there is a spacer 58 of electric insulating material and through which one of the pairs of rivets 55 is passed. The plates 53, 54 each have a portion projecting beyond the spacer 58 and toward the end wall 4, the projecting poraiaaais 652 has universal movement between the plates 88 and isheld in position by means of a rivet, or the like, (it provided with a convex head seating in a concave recess in the member 63 directly over the convex face 62. The opposite. end portions of the supporting member 63 are provided on their underfaces with contacts 65, 66 rigidly secured thereto, as at B1, and electrically connected with each other by means of the member 63 which is of metal, preferably copper. The contacts 65, 68 cooperate with contacts 68, 89 carried by terminal posts '88, II respectively secured in and projecting through apertures 12 in the bottom wall 2. The posts 10 and "H are preferably rigidly fixed in position by nuts i3 screw-threaded thereon, and each post is preferably provided with a lead wire clamping a nut 14. Also projecting into the casing l through the bottom wall 2 there is a third terminal I5 having a similar binding post nut; 16. The external ends of the posts 78, H and 15 are enclosed by a cup-shaped cover member 11 having an opening 18 for the passage of the electric lead wires. The post 18' is preferably shielded from the posts H and 15 by a partition 19 depending from the bottom wall 2.

Vertically through the partition 8 and directly above the lever member stepped portion 41 there is a cylindrical bore which serves as a guideway for a plunger or thrust member 8! which normal- Iyseats on the stepped portion 41. The upper end portion of the bore 88 is of enlarged internal diameter and internally screw-threaded, as at 82, providing an upward facing, annular shoulder 83. The thrust member 8i also has its upper portion of reduced external diameter to provide an upward facing shoulder 84 on which is seated the lower, circur'nferentially flanged end of a spring follower sleeve 85. Surrounding the sleeve 85 and seating on the circumferential flange thereof, there is a helical coil spring 86 which is held under compression and normally acts to move the thrust member 8! downward. The upper end of the spring 86 seats against a downward facing, annular shoulder 81 formed in an externally threaded sleeve member 88 which is screw-threaded into the threaded bore 82 and which is sleeved on the thrust membeis an. Surrounding the upper end of the sleeve member 88 which projects above the partition 8 there is a collar 89 having radial and vertically extended stop faces 90, 9| which cooperate with an abutment 92 carried by the partition l3 to limit rotation of the collar 89. The collar 89 is fixed to the sleeve member 88 by a set screw, or the like, 93, see Fig. 3. A circular plate 94 which provides a finger grip for rotating the sleeve member 88 is clamped to the top face of the collar 88 by a sleeve nut 95 which is threaded into the collar 89. The plate 94 is provided on its circumferonce with a pointed projection-96 which cooperates with suitable indicia 91 carried by the plate member 6 to indicate the direction of rotation of the sleeve member 88 which will result in a lower or colder average temperature in or adjacent the evaporator. The thrust member 8| projects above the clamping nut 95 and is provided on its upper end with a hand engaging abutment 98 by which the thrust member 8| may be moved downward or into the casing. Projecting forward from the partition H there is a hollow boss 98 aligned. with the partition 8 and containing a detent through the sleeve conical to provide a cam face which cooperates with an inclined face I02 formed on the thrust member 8| for a purpose to be described. In ward movement of the detent I is limited by engagement thereof with an outward facing shoulder I03 formed in the guideway IOI. A spring I04 seats at its inner end in a cylindrical recess in the outer face of the detent I00 and is held under compression by means of a plug I adjustably screw-threaded, as at I08, in the enlarged outer end portion of the guide bore I0I, such that the spring I04 normally urges the detent I00- inwardly to the limit of its movement.

Within the compartment I2 there is a boss or extension I01, preferably integral with the partition 8 and rising from the top face of the partition I0 directly above the lever member 50. In the extension I01 there is a vertical, upward opened, cylindrical recess I08 which communicates at its-bottom end through a substantially rectangular slot I09 with the interior of the easing I beneath the partition I0. Vertically reciprocable in the slot I09 there is a lever member engaging or governing means I I0 which projects downward through an aperture III in the lever member 50 and which is provided at its lower end with a lateral extension or arm I I2 for engagement with the underface of the lever member 50 for a purpose to be described. The portion of the member IIO which is positioned within the recess I08 is in the form of a hollow rectangle and receives a helical coil spring II3 which is prevented from lateral movement by the walls of the recess I08, and which is held under compression between the bottom of the recess I08 and the horizontal top portion II4 of the member I I0 so that the spring I I3 normally tends to move the member I I0 upward and the .arm I I2 into engagement with the lever means 50.

Through the partition I I there is a bearing bore H5 in which is journaled a shaft IIS, preferably of electric insulating material, such as Bakelite. The bore H5 is of slightly enlarged internal diameter, as at II1, to receive a flange II8 carried by the member II8 to prevent longitudinal movement of the member II6 into the chamber I2. The member H6 is held in its bore by a sleeve member II9 having a polygonal and preferably rectangular flange I20 which seats and is secured in a rectangular recess I2I formed in the outer face of the partition II. Embedded or otherwise secured in the shaft II6 there is a metallic, cylindrical extension I22 which projects H9 and terminates adjacent the front wall of the casing I. A pin I23 is passed transversely through the extension I22 and has its end portions in overlying, abutting relation to the free end of the sleeve 29 to hold the portion I20 in its recess I2I. Journaled on the shaft II6 within the chamber I2 and in lateral engagement with the inside face of the partition II there is an operating lever I24 having a finger engaging portion I25 projecting upward through a slot l26-in the cover member 6 and by which the lever may be oscillated. The lever I24 is provided with a finger or arm I21 which overlies and engages the upper end of the oper-; ating member Hi), the member IIO being held in engagement therewith by the spring H3. Beyond the lever .124, the shaft I I5 is provided with a polygonal portion I28, preferably rectangular to receive a star or ratchet-wheel I29 such that the wheel is held against rotation relative to the shaft H5. A pin I30 is passed transversely through the portion I29 to prevent endwise movement of the lever I24 and wheel I29. The lever I24 carries a pawl I3I having a tooth I32 engageable with the notches in theratchet-wheel to normally maintain the lever I24 fixed relative to the shaft H6. The pawl I3I is pivotally carried by a stud I33 rigid with the lever I24 and is normally urged into engagement with the ratchet-wheel by a spring I34 having one end engaging the lever I24 and its other end engaging the pawl I3I. The shaft H6 is normally held against rotary movement in the bore II5 by fusible means such as a solder seal between the inner face of the sleeve H9 and the circumferential face of the shaft extension I22. The sleeve I I9 is surrounded by a resistance heating coil I35 having one terminal connected to the binding post 15 and having its other terminal connected to the binding post 1|, the resistance wire having sufficient inherent rigidity so that no support therefor is required to maintain it in the desired position with the coil I35 spaced cireumferentially from the sleeve I I9. When a twowire circuit is employed, the binding posts and are electrically connected so that the heating coil I35 is in series circuit with the com-" pressor motor of the refrigerating system.

The operation of our control device is as follows: The bulb element 21 is preferably positioned adjacent to or within the evaporator or low side element so that the pressure generated by the volatile fluid therein will correspond to the low side temperature. .As noted above, the terminal posts H and 15 are electrically connected by a suitable lead wire, and the terminal posts 10 and 15 are connected in series circuit wi h the motor which drives the compressor of t e refrigerating system. Assuming that the system is at rest and at room temperature, for example, the parts will be in the positions illustrated in the drawings. If now the line switch to the compressor motor is closed, current will flow through the motor, circuit contacts 58, 85, thesupporting bridge member 83, contacts 80, 69, the resistance heating coil I35, to binding post 15, and thence back to line. The compressor will now be operating and as the temperature of the evaporator decreases due to operation of the system, the temperature surrounding the bulb element 21 will decrease. As the temperature of the-evaporator decreases, the pressure of the volatile fluid in the bulb 21 and therefore in the chamber 21 will also decrease. The force exerted by the volatile fluid in the chamber 21 and which acts to maintain the lever means comprising the lever members 32 and 50 in the position shown will be opposed by the combined forces of the springs H and 86. The component of force exerted by the combined toggle springs 51 and transferred to the line of action of spring 4I acts in conjunction with the pressure in the chamber 21 when the lever means is in the position shown to exert sufiicient force on lever movement to produce a snap action of the lever 32, that is, on movement of lever 32 the said transferred componento-f force exerted by springs 51 decreases at a greater rate than the rate at which the force of spring 4I decreases as the toggle point of the levers approaches the line of centers. When the pressure within the chamber 21 plus the said transferred component of force of springs 51 decreases to a point such that the upward force exerted thereby on the lever member 32 becomes equal to the downward force of the combined springs H and 86, then the lever member 32 will move downward; However, substantially at the time of, but just prior to, movement or the toggle point or point oi engagement between the lever members 32 and ill, through the line of centers connecting pivot pin 35 and the switch contacts, the flange of sleeve 85 will engage the upward facing shoulder 83 to stop further expan sion of the spring 86, thereby eliminating any further action of this spring through the thrust member 8i upon the lever member 32. Movement of lever 32 up to this point of operation will be gradual. The pressure existing in the chamber 21 must now decrease further before the force exerted by the spring 4| alone will be sufiicient to move the toggle point over-center. When the force of the range determining spring ll acting upon the lever member 32 becomes sufilcient to overcome the pressure in the chamber 21, then the continued movement of lever 32 will result from the greater rate of decrease of the component of force of springs 51 as above described, so that thetoggle point will be moved quickly to and through the line of centers with a snap action. As the toggle point snaps through center, the toggle springs- 51 will snap the lever member 50 upward, pulling the contacts 65 and 66 quickly out of engagement with their respective contacts 68 and 69, thereby breaking the motor circuit and stopping operation of the reirigerating system. Upward movement of the lever member 50 will be limited by engagement of the member 50 with the lever member engaging means M0. The force of the springs 51] will react on the lever member 32 to rotate the same clockwise about the shaft 35 as the toggle point breaks downward, the downward movement of the member 32 being limited by engagement of the stop laces 46 with the inside iaceioi the bottom wall 2. With the compressor at rest, the motor having been stopped, the temperature within and adjacent the evaporator will commence to rise causing expansion of the volatile fluid within the bulb element El and a building up pressure within the chamber ill. When the pressure within the chamber 2i becomes equal to and slightly exceeds the downward force exerted by the range determining spring it plus ti downward component of springs bl transre-cred to the line oi action oi springdi, then the lever member will be moved upward, lifting the point oi engagement between the lever mem= and toward the line or centers. This upward movement will be a quick substantially snap action from initial movement of lever mem= due to the said transierred component oi force decreasing at greater rate than the rate increase of force pi spring ii on the lever till. Since the lower end of the thrust member Oi stands substantially on the line of centers when the toggle mechanism is broken upwardly, as shown in 2, it is obvious that the line of centers when the toggle mechanism is broizen downward to switch opening position will pass through the thrust member 8i above its lower extremity. Therefore, prior to the toggle point or the. point of engagement between the lever members reaching the line oi centers, the stepped portion M will engage the lower end of the thrust member Bi. The pressure within the chamber 2'! must now build up sufflciently to overcome the combined resistance or the spring 4! and'the spring 86 in order to move the toggle point upwardly over-center. be apparent that the spring lid determines the differential operation of the control device/the greater the tension or downward iorce exerted It will therefore by spring til against upward movement of the thrust member ill, the higher the temperature surrounding the bulb element 271 will have to be in order to move the toggle point over-center so that the toggle springs M can move the lever member 5t downward to make contact between the contacts 65, 65 and 68, 69 respectively. When the force exerted on the lever member 32 by the power element i8 becomes great enough to overcome the force of the range determining spring 4i and the differential determining spring -86, then the lever member 50 will be moved downward by the toggle springs 51 with a snap action, the springs 51 reacting on the lever member 32 to snap the same upwardly in a counter-clockwise direction about its fulcrum 35, upward movement of the member 32 being limited by engagement of the stop faces 45 with the inclined underface 9 of partition 8. The refrigerating system will now again be in operation and the temperature in and adjacent the evaporator will decrease with a resulting circuit breaking opera tion of the control device, as above described. The force of the range determining spring is preferably set at the factory by adjustment of I the screw iii to provide the proper cutting out point for the refrigerating system, that is, to set the low temperature limit of the evaporator. The high temperature limit at which the system will be started or cut in may be manually adjusted by rotation of the plate ilt, rotation of the plate it in the direction of the arrow, Fig. 5, or counter-clockwise, resulting in a colder or lower average temperature within or adjacent the evaporator. Counter-clockwise rotation or the plate 94 and therefore of the sleeve member 88 will relieve the tension on the spring 86 so that the pressure within the chamber ill and required to start operation of the system will be less and will be in accordance with counter-clockwise rotation of the plate lit. A stop 92 cooperable with the stop faces till, 9i rigid with the plate it serves to determine the minimum and maximum temperature at which the system may be operated.

The function of the spring 86 is to provide what is commonly referred to as a cold control for the control device and refrigerating"system.

A defrosting control by which the temperature of the evaporator may be raised to a pointat which the ice externally collected thereon will melt is provided and functions as follows: When it is desired to defrost the rnachiie or reiriger" ating apparatus, the plunger or thrust member 8i is moved downward or inward by of the hand engaging abutment 98. As the thrust mem ber Si is moved downward, th high point of the cam face ibil'will pass beyond or below the high point of the detent tilt, the detent moving inward into engagement with the cam W2 the high points pass each other, such movement being caused by the compression spring tilt. The thrust member 8i may be moved downward respective of the position of the lever means,

and if the switch contacts are in closed position as shown, the downward movement of the thrust member 8i will carry the toggle point below the line of centers and cause the switch to be opened, thereby stopping the compressor motor. Regardless of whether the switch was in open or closed position when the thrust member M was moved inward or downward to effect defrosting oi the system, the pressure inthe chamber 2'! requisite to movement of the switch to closed position will now have to be considerably greater than is required for normal operation as the additional "iii sov

force of the spring I04 acting through'the cam surfaces must also be overcome. When the pressure in the chamber 21 has built up sufliciently to force the detent I outwardly by the cam action of the face I02, the force exerted by the power element It will be suflicient to move the switch to closed position with a continuous, uninterrupted movement as the force is greater than that required to overcome the combined force of also provided, and their operation is as follows:

Should the compressor motor become overloaded for an appreciable time such as to endanger the motor, the current flowing through the coil I will increase. The increased current flow through the coil I35 will raise its temperature sufficiently to heat and melt the solder bond or fusible connection between the sleeve H9 and the shaft extension I22. As the shaft extension I22 is released, the spring II3 will expand as it is no longer opposed and will move the lever member engaging or governing means III) upward, bringing the arm I I2 into engagement with the underside of the lever member with suflicient force to overcome the component of force exerted by the toggle springs 5'I.and lift the lever member 50 upward about its knife edges to break contact between the contacts 65, 66 and 68, 69 respectively, thereby breaking the compressor motor circuit and stopping the refrigerating system.-

This upward movement of the engaging means.

0 will throw the'flnger engaging portion I25 of the lever I24 toward the right, facing Figs. 1 and 2, which is the "of!" position of the lever I24 and indicates that the system has been either automatically stopped or manually stopped, as will be described. The system may be again started by manual movement of the lever I24 through the medium of the portion I25, by movement of the portion I25 manually toward the left, facing Figs. 1 and 2. As the lever is moved counter-clockwise, or to the left as above stated, the pawl I3I will ride over the adjacent projection on the ratchetwheel and snap into position in the next notch, taken in a counter-clockwise direction facing Fig. 2, which will result in a movement of the arm I21 to the position shown in Fig. 2. Movement of the arm I21 to the position of Fig. 2 can only be effected by compression of the spring H3 and downward movement of the lever engaging means I II to the position shown, which will release the lever member 50 and permit the toggle springs 51 to close the switch in the event the temperature in or adjacent the evaporator is at or above the maximum desired degree. The foregoing resetting of the, switch mechanism is, of course,

rotated when sumcient force is exerted to cam the pawl I3I outward against the force of the pawl spring I34. This manual movement of the lever- I25 in a clockwise direction will lift the arm I21, permitting the spring II3 to expand and lift the arm II2 into contact breaking engagement with the lever member 50. The switch may be closed after manual opening of the same by movement of the lever I24 in a counter-clockwise direction upon the exercise of sufficient force both to cam the pawl I3I outward and into its next adjacent notch and to overcome the forced spring II3.

What we claim and desire to secure by Letters Patent of the United States is:

1. A control device of the character described, comprising a control means, lever means for actuating said control means, a power element for moving said lever means in one direction, means resisting operation of said element, a thrustmember operable on said lever means, means cooperable with said resisting means-and acting through said thrust member to oppose operation of said element, means to adjust the opposing force of said last-named means, and means en gageable with said thrust member for increasing the resistance to operation of said element without increasing the resisting force exerted by said first-named cooperablemeans.

2. A control device of the character described:

comprising a control means, lever means for actuating said control means, a power element for moving said lever means in one direction, means resisting operation of said element, a manually movable thrust member operable on said lever.

means, means cooperable with said resisting means and acting through said thrust member to oppose operation of said element, and .means cooperable with said thrust member upon manual movement thereof toward said lever means for:

increasing the resistance to operation of said element which is exerted by said first-named cooperable means. a

3. A control device of the character described, comprising a control means having two positions of rest, a lever member having a fulcrum support, a power element for moving said lever member in one direction to move said control means to one of said positions, means resisting operation of said element and operable to move saidi control means to the other of said positions, a second lever member 'operatively connecting said control means to said power element and said resisting means and pivotally supported by said first-named lever member, spring means acting on said second-named levermember and operable upon movement of said first-named lever member to move said'second-named lever member, means to hold said control means in one of said positions, and means acting on said first-'- eration of said element, and temperature respon- 6 arsenic sive safety means cooperable with and acting on said second-named lever member to actuate said control means.

5. A control device of the character described, comprising an electric switch, a lever member having a fulcrum support, a power element for moving said lever member in onedirection, means resisting operation of said element, a second lever member for actuating said switch and piv-= otally supported by said first-named lever member, spring means acting on said second-named lever member and operable upon movement of said first-named lever member to move said/secend-named lever member, means acting on said first-named lever member to oppose operation of said element, an electric resistance element in circuit with said switch, and means responsive to temperature created by said resistance element to move said switch to open position.-

6. A control device of the character described, comprising an electric switch, a lever member having a fulcrumsupport, a power element for moving said lever member in one direction, means resisting operationof said element, a second lever member for actuating said switch and pivotally supported by said first-named lever member, spring meansacting on said second-named lever member and operable upon movement of said first-named lever member to move said secondnamed lever member, a reciprocable thrust member cooperable with said first-named lever member, a spring acting upon movement of said thrust member by said first-named lever member to oppose operation or" said element, said thrust member being manually operable to move said switch to open position, and means operable upon manual movement of said thrust member to resist movement of said thrust member by said first-named lever member whereby to increase the force of said power element necessary to close said switch.

l. A control device of the character described, comprising an electric switch, a lever member having a i'ulcrum support, a power element for moving said lever member in one direction, means resisting operation of said element, a second lever member for actuating said switch and piv otally supported by said first-named lever mem ber, spring means acting on said second-named lever member and operable upon movement of said first-named lever member to move said second named lever member, a reciprocable thrust member cooperable with said first-named lever member, a spring acting upon movement of said thrust member by said first-named lever Kil8l'i1== ber to oppose operation of said element, said thrust member being manually operable to move said switch to open position, means operable upon manual movement of said thrust member to resist movement of said thrust member by said first named lever member whereby to increase the force of said power element necessary to close said switch, an electric resistance element in circuit with said switch, means responsive to tempera ture created by said resistance element to move said switch to open position, said last-named re sponsive means having means cooperable with said second-named lever member and operable to overcome said spring means, and manna means cooperable with said last-named means to move said switch to closed position upon move= ment or said switch to open position by said lastnamed responsive means.

8. A control device of the character described, comprising an electric switch, a lever member having a fulcrum support, a power element for moving said lever member in one direction, means resisting operation of said element, a second lever member for actuating said switch and piv otally supported by said first-named lever mem ber, spring means acting on said second-named lever member and operable upon movement oi said first-named lever member to move said second-named lever member, a reciprocable thrust member cooperable with said first-named lever member, a spring acting upon movement of said thrust member by said first-named lever member to oppose operation of said element, said thrust member being manually operable to move said switch to open position, means operable upon manual movement of said thrust member to resist movement of said thrust member by said first-named lever member whereby to increase the force of said power element to close said switch, an electric resistance element in circuit with said switch, means normally acting to move said switch to open position, and fusible means resisting said last-named means, said fusible means responding to rise of temperature created by said resistance element to release said lastnamed normally acting means.

9. A device of the character described, comprising a control means having two positions, a toggle mechanism including a lever and an arm iulcrumed thereon, said arm being operatively connected to said control means to move said control means to one or the other of said positions upon movement overccnter, a movable resistance member having a portion engageable by said lever, means urging said resistance member portion to a position intermediate the lines of centers oi said toggle mechanism, said resistance member being engaged by said lever on niovernent in one direction prior to movement overcenter to oppose movement of said toggle mechanism in said one direction, and means to limit movement of said resistance member by said urging means short of overcenter movement of saidrtoggle mechanism in the opposite direction such that said resistance member will be inefiective to urge said toggle mechanism overcenter in said opposite direction.

iii. A device of the character described, comprising a control means having two positions, a toggle mechanism including a lever and arm iuicrumed thereon, said arm being operativeiy connected to said control means to move said control means to one or the other of said posi tions upon movement cvercenter, a movable re sistance member having a portion engageable by said lever, means urging said resistance member portion to a position intermediate the lines of cen ters of said toggle mechanism, said resistance member being engaged by said lever on movemerit in one direction prior to movementover center to oppose movement of said toggle mechanism in said one direction, means to limit move merit of said resistance member by said urging means short of overccntcr movement oi said toggle mechanism in the opposite direction such that said resistance member will be ineffective to urge said toggle mechanism overcenter in said opposite direction, and means cooperable with said resistance member to increase the opposition to movement of said toggle mechanism in said one direction.

ii. A device of the character described, comprising a control means having two positions, a toggle mechanism including a lever and an arm tulcrumed thereon, said arm being operatively dtli connected to said control means to move said control means to one or the other of said positions upon movement overcenter, a movable resistance member having a portion engageable by said lever, means urging said resistance member portion to a position intermediate the lines of centers of said toggle mechanism, said resistance member being engaged by said lever on movement in one direction prior to movement overcenter to oppose movement of said toggle mechanism in said one direction, means to limit movement of said resistance member by said urging means short of overcenter movement of said toggle mechanism in the opposite direction such that said resistance member will be inefiective to urge said toggle mechanism overcenter in said opposite direction, and means cooperable with said arm to move said control means relative to said lever.

12. In a device of the character described, an operating lever, a control means operable by said lever, a thrust member longitudinally reciprocal in the plane of movement of said lever and engageable thereby, a spring urging said thrust member into position for engagement by said lever such that said spring will oppose movement of said lever in one direction, means to limit movement of said thrust member by said spring in the opposite direction such that said lever is moveable out of engagement with said thrust member, means to actuate said lever, and means to hold said control means in inactive position irrespective of actuation of said lever by said last-named means.

13. In a device of the character described, an operating lever, a control means operable by said lever, a thrust member longitudinally reciprocal in the plane of movement of said lever and en'- gageable thereby, spring means urging said thrust member into position for engagement by said lever such that said spring means will oppose movement, of said lever in one direction, means to limit movement of said thrust member by said spring means in the opposite direction such that said lever is moveable out of engagement with said thrust member, means operable without increasing the force exerted by said spring means and cooperable with said thrust member to increase the resistance 01 said thrust member to movement of said lever in said one direction, and means to actuate said lever.

14. In a device of the character described, an operating lever, a control means operable by said lever, a thrust member'longitudinally reciprocal in the plane of movement oi said lever and engageable thereby, a spring urging said thrust member into position for engagement by said lever such that said spring will oppose movement of said lever in one direction, means to limit movement of said thrust member by said spring in the opposite direction such that said lever is movable out of engagement with said thrust member, said thrust member being movable beyond said limit of movement, means operable upon such movement of said thrust member to increase the resistance 01' said thrust member to movement of said lever in said one direction, and means to actuate said lever.

15. A control device of the character described, comprising an electric switch, a lever member having a fulcrum support, a power element for moving said lever member in one direction, means resisting operation of said element, a second lever member for actuating said switch and pivotally supported by said first-named lever member, spring means acting on said second-named lever member and operable upon movement of said first-named lever member to move said secondnamed lever member, means acting on said firstnamed lever member to oppose operation of said element, an electric resistance element in-circuit with said switch, a spring under stress and tendin to move said switch to open position, releasable means holding said spring against movement, and means responsive to temperature created by said resistance element to release said releasable means so that said last-named spring can open said switch.

16. In a device of the character described, a control means movable from and to predetermined positions, automatically acting means operatively connected to and for actuating said control means, governing means for moving said control means to one of said positions in opposition to said automatically acting means, said governing means comprising a slide member, means acting to move said slide member, a movable member having a stop position for holding said last-named means against actuation, fusible material securing said movable member in said stop position, and a heating means for tusing said material.

1'11 In a safety device, a supporting member, a tubular element mounted on said member and held against movement about its longitudinal axis, a rotatable member journaled in said element and projecting therefrom, fusible material securing said rotatable member to said tubular element, an operating element stressed for movement in one direction, means operable by said rotatable member and opposing movement of said operating element, and heating means for .i'using said fusible material so that said operating element can move.

LEWIS W. EGGLESTON. EARNEST J. DILLMAN. 

